[mm PATCH v3 01/23] arch/arc: Add option to skip sync on DMA mapping

From: Alexander Duyck
Date: Thu Nov 10 2016 - 12:35:37 EST


This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to
avoid invoking cache line invalidation if the driver will just handle it
later via a sync_for_cpu or sync_for_device call.

Acked-by: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx>
---
arch/arc/mm/dma.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/arc/mm/dma.c b/arch/arc/mm/dma.c
index 20afc65..6303c34 100644
--- a/arch/arc/mm/dma.c
+++ b/arch/arc/mm/dma.c
@@ -133,7 +133,10 @@ static dma_addr_t arc_dma_map_page(struct device *dev, struct page *page,
unsigned long attrs)
{
phys_addr_t paddr = page_to_phys(page) + offset;
- _dma_cache_sync(paddr, size, dir);
+
+ if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC))
+ _dma_cache_sync(paddr, size, dir);
+
return plat_phys_to_dma(dev, paddr);
}